i disagree with this very strongly
. As a web developer, its important to develop for all browsers. I check on at least 4 browsers that a design of a site is working. I browse with opera and mozilla and if a site doesnt design to these formats then i wont view it, its lazy programming in my opinion. Its similar to page width - you still shouldnt design a website that will have a horizontal scroll bar on a 800 pixel resolution - as there is still a huge % of the web which are on this. And losing that many visitors is just silly over something that can be avoided very easily.
It isnt that difficult - all you have to do is just dont use ie only tags.
It isnt a problem so much anymore - but say 5 years ago it was a big problem. Back then, before css etc, html code was about 80% standard. However the rest of the code which you could you use was wither netscape only or internet explorer only code. They soon realised that this wasnt good and both browsers starting to design them so that developers could use the other code - but there are still some ie only tages. eg <marquee>